In some distributed applications, computer programs are called upon to perform sensitive operations in untrusted environments. For example, vendors of digital goods like music and software may wish to control a consumer's use of those goods. One way to do this is to run a special rights-management program on the consumer's computer system or playing device that enforces the terms of the consumer's contract with the vendor. To increase performance and fault tolerance, and to facilitate a flexible range of business relationships between vendor and consumer, such a program may avoid communicating with other systems for relatively long periods of time. As a result, the program may need to store a variety of sensitive, transaction-related data—such as account balances, purchase receipts, usage records, budgets, billing records, and the like—on the consumer's system. Although the program may occasionally send this information to a trusted computer for processing, this type of communication may be limited for performance, fault tolerance, privacy, or other reasons.
In such a system, the consumer may have both the incentive and the opportunity to alter the vendor's rights management program in order to obtain unauthorized benefits. While it may not be possible to secure the rights management program completely, since the consumer will typically have ultimate control over the underlying hardware and the operating system, a number of software and hardware platforms are emerging that reduce the risk of attack. These platforms typically include a processing environment that allows authorized programs to run with reduced risk of reverse engineering and tampering. For example, this may be achieved with a hardware package containing a processor, memory, and some tamper-detecting circuitry, and/or by various techniques for software obfuscation and tamper detection. However, these platforms typically do not provide trusted, persistent storage in bulk, as it is generally difficult to prevent read and write access to devices such as disk drives and flash memory from outside the trusted platform. Thus, if sensitive records are stored locally, attackers might try to read, modify, add, or delete those records in order to undermine effective enforcement of the terms of their contract with the vendor. Systems and methods are thus needed for providing trusted bulk storage in potentially untrusted computing environments.